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l @uiten tstt stmt- @Hita IMPROVEMENI HOISTING JAGKS.

J. w. STEED, or MINNEAPOLIS, MINNESOTA. Letters' Patent No. 60,080, dated Mvember 27, 1866,

Y SPECIFICATION. TO ALL IT MAY CONC'ERN: I i

Be it known that I, J. W.STEED, of Minneapolis, in the county of, Hennepin, and State of Minnesota,

have invented certain new and useful Improvements in Hoisting Jacks; and Ido hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings making' part ot' this specification, and to the letters of reference markedthereon, like letters indicating like parts, wherever they occur. To enable others skilledin the art to construct and use the invention, I will proceed to describe it. I

My inventionrrelates tothat class of inzlplenlents used for elevating or lifting heavy'weights, usually denominated jack screws; and consists in providing aseries of conical friction rollers,`interposed between the cap and the shoulder or flange upon the upperportion of the screw, to lessen the friction between the parts.

Figure 1 is a side elevation, with the upper portion shown in section.

B igure 2 is a plan view of the frictionl rollers mounted in their frameand detachedfrom'the implement.

A represents the body of the jack, which `is made of cast iron, usually, and made hollow. B represents a `screw fitting into a suitable screw cut for it in the upper portion of the body, A. `This screw,- B, is provided with a strong projecting block or flange, C, which isl attached 'rigidly to the screw, B, and turnsrwithit.; the projection, 0,*being provided with a series of holes for the insertion cfa lever to turn the screw. Upon the projecting ange, C, a series of conical rollers, a, mounted in a circular frame, consisting of `two rings, c ande, as

`shown 'in fl'g. 2, are placed, the upper surface of the ange, C, being suitably grcoved to form a track for them,

as shown in iig. 1. A cap, D, is placed on the rollers, and has its'under surface similarly grooved` to fit the rollers, a this cap, D, having a hole bored vertically through its centre to receive thestem or journal, b, of the screw, which projects, as shown in g. 1, to keep the cap, D,'in place. It will thus berseen that-when the jack is placed under any "weight to be raised, the whole weight of 'the object will be thrown `upon the rollers a, and' that' by the use of these rollers the screw can be turned with ease.

Having thus describedmy invention, what I claim as new, anddesire to secure'by Letters Patent, is The combination of the cap D, and the screw B, with the ilange C, and the conical rollers a, arranged and operating substantially as and for the purpose set forth. 'i Y i J. W..STEED..

Witnesses p J. C. WILLIAMS,

Josmn ESPY. 

